A Study of Hazardous Air Pollutants at the Tidd PFBC Demonstration Plant

Program is a joint effort between government and industry to develop a new generation of coal utilimtion processes. In 1986, the Ohio Power Company, a subsidiary of the American Electric Power Service Corporation (AEP), was awarded cofunding through the CCT program for the Tidd Pressurized Fluidixed Bed Combustor (PFBC) Demonstration Plant located in Brilliant, Ohio. The Tidd PFBC unit began operation in 1990 and was later selected as a test site for an advanced particle filtration (APF) system designed for hot gas particulate removal. The APF system was sponsored by the DOE Morgantown Energy Technology Center (METC) through their Hot Gas Cleanup Research and Development Program. A complementary goal of the DOE CCT and METC R&D programs has always been to demonstrate the environmental acceptability of these emerging technologies. The Clean Air Act Amendments of 1990 (CAAA) have focused that commitment toward evaluating the fate of hazardous air pollutants (HAPS) associated with advanced coal-based and hot gas cleanup technologies. Radian Corporation was contracted by AEP to perform this assessment of HAPS at the Tidd PFBC demonstration plant with funding from the DOE-METC Hot Gas Cleanup R&D program. The objective of this study is to assess the major input, process, and emission streams at Plant Tidd for the HAPS identified in Title III of the CAAA. Site Description The boiler at Plant Tidd is a bubbling bed, pressurized fluidized bed combustor (PFBC) rated at 70 MWe; 55 MW is produced by a steam turbine generator and 15 MW is produced by depressurizing the hot flue gas in a gas turbine generator. Total plant load during the test period was steady at 45 to 46 MW, which is representative of stable, long-term operation. A slurry of Pittsburgh No. 8 bituminous coal (3.4% sulfur) is fed to the PFBC unit along with dolomite sorbent to control SO, emissions. Particulate matter is controlled by primary and secondary cyclones in series with an electrostatic precipitator (ESP). Formation of NO, is minimized because of relatively low combustion temperatures within the PFBC process. An additional feature of the Plant Tidd facility is a demonstration-scale hot gas clean-up system. Treated gas from one of the seven cyclones is directed to a ceramic barrier, advanced particle filter (APF), and backup cyclone. The treated gas is then returned to the process upstream of the ESP. The APF operated at approximately 1350°F during the test period. The ceramic candles were backpulsed …